In communications networks, there may be a challenge to obtain good performance and capacity for a given communications protocol, its parameters and the physical environment in which the communications network is deployed.
For example, one parameter in providing good performance and capacity for a given communications protocol in a communications network is the capabilities of the radio transceiver devices operating in the communications network. Examples of such radio transceiver devices include both radio access network nodes and portable wireless devices. For example, the radio transceiver devices comprise receivers in order to receive signals from another radio transceiver device or node in the communications network.
As is known by the skilled person, a receiver in a radio transceiver device comprises circuitry configured to perform operations on received signals. One such operation is gain control, or automatic gain control (AGC).
AGC currently exist in radio access network nodes with antennas where the different antenna signal chains are independent of each other. Current radio access network nodes are based on a receiver architecture where there typically are a low number of parallel receiver branches (say, about 2-4) with separate detectors and control loops in each receiver branch. Such an antenna architecture is not possible to implement in an array antenna system using combining before detection.
More particularly, in antenna array systems with a large number of antennas (say, more than 4 antennas), each antenna is connected to low noise amplifiers and then combined into one received signal. In this combined received signal distributed to a detector it is not possible to control the individual antenna signal paths based on the combined received signal at the detector. It is not possible to detect if the signal in one path is saturated and thus distort the combined received signal.
Hence, there is still a need for an improved gain control in a receiver in a radio transceiver device.